This invention relates to a unique integrated wall assembly which is useable per se as an insulation assembly, or as a constituent insulation component of a solid rocket motor while disposed internally of the casing of the solid rocket motor, or as a mandrel for filament-winding a solid rocket motor case.
The internal insulation used in filament-wound solid rocket motors is usually elastomeric material containing an assortment of filler materials. This insulation is assembled in a mold by laying up plies of uncured sheet material to produce the desired thickness, and then curing the assembly under pressure and heat. The cured insulation assembly is incorporated into the filament wind mandrel and is integrally bonded to the motor case formed by the winding process.
The process described above is very time consuming, expensive, and of concern from a reliability aspect. More specifically, the uncured insulation sheet material is difficult to process. It must be cut into precise patterns in order to fit the mold. Additionally, interlaminar adhesion of the cut elements is poor, and air entrapment is a continual problem. Further, quality assurance of the finished product is dependent upon detecting voids and deliminations by means of ultrasonic inspection and x-ray. These methods are expensive and not as reliable as desired.
Elastomeric insulation used in present day solid rocket motors is the result of extensive development in an attempt to overcome the above-described problems. Although there are many variations in the elastomer and the filler used, it is fair and accurate to say that none of these variations have resulted in any significant improvement in insulating efficiency.